An ink jet printer is as an example of a printing apparatus that ejects droplets of ink onto a recording medium such as a sheet of paper, for printing an image of the recording medium. The ink jet printer includes a head unit having an ink jet head provided with an ink cartridge that accommodates the ink. In operation of the head unit, the ink is supplied from the ink cartridge to each ink jet head having ejection nozzles, so that a printing operation is performed by ejection of the ink droplets from selected ejection nozzles.
There are two general types of ink used in inkjet printers, dye-based ink and pigment-based ink. However, dye-based and pigment-based ink types are not interchangeable. Each ink type offers specific advantages over the other. In general dye inks tend to be cheaper but offer lower print quality than pigment inks.
Switching a print engine from operating using one ink type to operating with the other ink type necessitates a long and expensive process, and is generally not even considered as practical for production print houses. Therefore, a print house must choose one ink type for its printing operation, or purchase and operate two printers (one for each ink type) in order to have an ability to print using both print ink types.
However, high speed ink jet production printers may have a purchasing price as high as $3 million, which may limit the ability of some printing houses to operate printers that print using each ink type.
Accordingly, an ink-jet printer capable of efficiently operating with multiple ink types is desired.